But scientists say they are studying what would happen if the volcano has a repeat of a far bigger eruption in 1963. (scientificamerican.com)
The rebuttal is that if this were true, then the CO2 records would show big jumps at the time of big eruptions, and they don't. (illconsidered.blogspot.ru)
The last big eruption in 1963 was preceded by continuous tremors. (theguardian.com)